Aspergillus fumigatus is one of the most common Aspergillus species known to cause disease in humans. A. fumigatus is the most frequent cause of invasive fungal infection in immunosuppressed individuals, which include patients receiving immunosuppressive therapy for autoimmune or neoplastic disease, organ transplant recipients, and AIDS patients. A. fumigatus primarily causes invasive infection in the lung and represents a major cause of morbidity and mortality in these individuals. Additionally, A. fumigatus can cause chronic pulmonary infections or allergic disease in immunocompetent hosts. An A. fumigatus infection most commonly manifests as invasive pulmonary aspergillosis.
Only a few molecular assays exist for the detection of invasive fungal infections, including galactomannan and beta-glucan as well as DNA-based assays (e.g., PCR). The galactomannan and beta-glucan assays have limitations in terms of specificity and sensitivity. For example, antifungal medication is known to interfere with the galactomannan assay. A. fumigatus does not release much DNA into the circulation, which limits the utility of DNA-based assays. Therefore, there is a need for a sensitive assay to detect the presence of A. fumigatus in a sample from an infected patient.